1. Field of the Invention
The present invention relates to a signal processing method for band compression of a video signal, and to a recording and reproducing device for recording and reproducing the band-compressed signal.
2. Prior art
There are six known methods of coding a video signal: in-frame or in-field coding, inter-frame or inter-field coding predicted from the preceding frame or field, and frame or field interpolation coding using information obtained by interpolation form the frame or field before and after the coded frame or field.
There are no problems with the use of either in-frame or in-field coding or inter-frame or inter-field coding because the frame sequence of the input video signal and the frame sequence of the encoded output signal are the same.
If the frame sequence of the input and output signals is kept the same during interpolation coding, in which the current field or frame is coded based on information interpolated form the fields or frames before and after the current field or frame is used, however, decoding of the output signal requires a buffer (frame memory) of sufficient capacity to hold the data for at least the plural frames required for interpolation.